On Wed, 18 Jul 2012, Lan Tianyu wrote: > On 2012/7/18 22:19, Alan Stern wrote: > > An alternative to her suggestion would be to disconnect the device when > > the port goes off. When the port is powered back on, the device will > > be rediscovered and probed again. > hi alan: > Reprobe may cause the devnum change. Userspace will treat it a > different device from previous one. e.g app held the device node fd, > After port went off and on, device reprobed and the fd became invalid.
That's right. Your argument suggests that power-off should be controlled by userspace, not by the kernel, and it should happen only when no app is holding the device node open. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
